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Zepeda-Rivera M, Minot SS, Bouzek H, Wu H, Blanco-Míguez A, Manghi P, Jones DS, LaCourse KD, Wu Y, McMahon EF, Park SN, Lim YK, Kempchinsky AG, Willis AD, Cotton SL, Yost SC, Sicinska E, Kook JK, Dewhirst FE, Segata N, Bullman S, Johnston CD. A distinct Fusobacterium nucleatum clade dominates the colorectal cancer niche. Nature 2024; 628:424-432. [PMID: 38509359 PMCID: PMC11006615 DOI: 10.1038/s41586-024-07182-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 02/08/2024] [Indexed: 03/22/2024]
Abstract
Fusobacterium nucleatum (Fn), a bacterium present in the human oral cavity and rarely found in the lower gastrointestinal tract of healthy individuals1, is enriched in human colorectal cancer (CRC) tumours2-5. High intratumoural Fn loads are associated with recurrence, metastases and poorer patient prognosis5-8. Here, to delineate Fn genetic factors facilitating tumour colonization, we generated closed genomes for 135 Fn strains; 80 oral strains from individuals without cancer and 55 unique cancer strains cultured from tumours from 51 patients with CRC. Pangenomic analyses identified 483 CRC-enriched genetic factors. Tumour-isolated strains predominantly belong to Fn subspecies animalis (Fna). However, genomic analyses reveal that Fna, considered a single subspecies, is instead composed of two distinct clades (Fna C1 and Fna C2). Of these, only Fna C2 dominates the CRC tumour niche. Inter-Fna analyses identified 195 Fna C2-associated genetic factors consistent with increased metabolic potential and colonization of the gastrointestinal tract. In support of this, Fna C2-treated mice had an increased number of intestinal adenomas and altered metabolites. Microbiome analysis of human tumour tissue from 116 patients with CRC demonstrated Fna C2 enrichment. Comparison of 62 paired specimens showed that only Fna C2 is tumour enriched compared to normal adjacent tissue. This was further supported by metagenomic analysis of stool samples from 627 patients with CRC and 619 healthy individuals. Collectively, our results identify the Fna clade bifurcation, show that specifically Fna C2 drives the reported Fn enrichment in human CRC and reveal the genetic underpinnings of pathoadaptation of Fna C2 to the CRC niche.
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Affiliation(s)
- Martha Zepeda-Rivera
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Samuel S Minot
- Data Core, Shared Resources, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Heather Bouzek
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Hanrui Wu
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Aitor Blanco-Míguez
- Department of Computational, Cellular and Integrative Biology, University of Trento, Trento, Italy
| | - Paolo Manghi
- Department of Computational, Cellular and Integrative Biology, University of Trento, Trento, Italy
| | - Dakota S Jones
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | | | - Ying Wu
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Elsa F McMahon
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Soon-Nang Park
- Korean Collection for Oral Microbiology and Department of Oral Biochemistry, School of Dentistry, Chosun University, Gwangju, Republic of Korea
| | - Yun K Lim
- Korean Collection for Oral Microbiology and Department of Oral Biochemistry, School of Dentistry, Chosun University, Gwangju, Republic of Korea
| | | | - Amy D Willis
- Department of Biostatistics, University of Washington, Seattle, WA, USA
| | | | | | - Ewa Sicinska
- Department of Pathology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Joong-Ki Kook
- Korean Collection for Oral Microbiology and Department of Oral Biochemistry, School of Dentistry, Chosun University, Gwangju, Republic of Korea
| | - Floyd E Dewhirst
- Forsyth Institute, Cambridge, MA, USA
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - Nicola Segata
- Department of Computational, Cellular and Integrative Biology, University of Trento, Trento, Italy
| | - Susan Bullman
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
| | - Christopher D Johnston
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
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2
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Galeano Niño JL, Wu H, LaCourse KD, Srinivasan H, Fitzgibbon M, Minot SS, Sather C, Johnston CD, Bullman S. INVADEseq to identify cell-adherent or invasive bacteria and the associated host transcriptome at single-cell-level resolution. Nat Protoc 2023; 18:3355-3389. [PMID: 37789194 PMCID: PMC10790651 DOI: 10.1038/s41596-023-00888-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 07/11/2023] [Indexed: 10/05/2023]
Abstract
Single-cell RNA sequencing (scRNAseq) technologies have been beneficial in revealing and describing cellular heterogeneity within mammalian tissues, including solid tumors. However, many of these techniques apply poly(A) selection of RNA, and thus have primarily focused on determining the gene signatures of eukaryotic cellular components of the tumor microenvironment. Microbiome analysis has revealed the presence of microbial ecosystems, including bacteria and fungi, within human tumor tissues from major cancer types. Imaging data have revealed that intratumoral bacteria may be located within epithelial and immune cell types. However, as bacterial RNA typically lacks a poly(A) tail, standard scRNAseq approaches have limited ability to capture this microbial component of the tumor microenvironment. To overcome this, we describe the invasion-adhesion-directed expression sequencing (INVADEseq) approach, whereby we adapt 10x Genomics 5' scRNAseq protocol by introducing a primer that targets a conserved region of the bacterial 16S ribosomal RNA gene in addition to the standard primer for eukaryotic poly(A) RNA selection. This 'add-on' approach enables the generation of eukaryotic and bacterial DNA libraries at eukaryotic single-cell level resolution, utilizing the 10x barcode to identify single cells with intracellular bacteria. The INVADEseq method takes 30 h to complete, including tissue processing, sequencing and computational analysis. As an output, INVADEseq has shown to be a reliable tool in human cancer cell lines and patient tumor specimens by detecting the proportion of human cells that harbor bacteria and the identities of human cells and intracellular bacteria, along with identifying host transcriptional programs that are modulated on the basis of associated bacteria.
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Affiliation(s)
| | - Hanrui Wu
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | | | - Harini Srinivasan
- Bioinformatics Shared Resources, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Matthew Fitzgibbon
- Bioinformatics Shared Resources, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Samuel S Minot
- Data Core, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Cassie Sather
- Shared Resources Administration, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Christopher D Johnston
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
| | - Susan Bullman
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
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3
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Zepeda-Rivera MA, Eisele Y, Baryiames A, Wu H, LaCourse KD, Jones DS, Hauner H, Dewhirst FE, Minot SS, Johnston CD, Bullman S. Fusobacterium sphaericum sp. nov. , isolated from a human colon tumor, is prevalent in various human body sites and induces IL-8 secretion from colorectal cancer cells. bioRxiv 2023:2023.06.16.545380. [PMID: 37398369 PMCID: PMC10312772 DOI: 10.1101/2023.06.16.545380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Cancerous tissue is a largely unexplored microbial niche that provides a unique environment for the colonization and growth of specific bacterial communities, and with it, the opportunity to identify novel bacterial species. Here, we report distinct features of a novel Fusobacterium species, F. sphaericum sp. nov. ( Fs ), isolated from primary colon adenocarcinoma tissue. We acquire the complete, closed genome of this organism and phylogenetically confirm its classification into the Fusobacterium genus. Phenotypic and genomic analysis of Fs reveal that this novel organism is of coccoid shape, rare for Fusobacterium members, and has species-distinct gene content. Fs displays a metabolic profile and antibiotic resistance repertoire consistent with other Fusobacterium species. In vitro, Fs has adherent and immunomodulatory capabilities, as it intimately associates with human colon cancer epithelial cells and promotes IL-8 secretion. Analysis of the prevalence and abundance of Fs in ∼1,750 human metagenomic samples shows that it is a moderately prevalent member of the human oral cavity and stool. Intriguingly, analysis of ∼1,270 specimens from patients with colorectal cancer demonstrate that Fs is significantly enriched in colonic and tumor tissue as compared to mucosa or feces. Our study sheds light on a novel bacterial species that is prevalent within the human intestinal microbiota and whose role in human health and disease requires further investigation.
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LaCourse KD, Zepeda-Rivera M, Kempchinsky AG, Baryiames A, Minot SS, Johnston CD, Bullman S. The cancer chemotherapeutic 5-fluorouracil is a potent Fusobacterium nucleatum inhibitor and its activity is modified by intratumoral microbiota. Cell Rep 2022; 41:111625. [PMID: 36384132 PMCID: PMC10790632 DOI: 10.1016/j.celrep.2022.111625] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 08/26/2022] [Accepted: 10/17/2022] [Indexed: 11/17/2022] Open
Abstract
Fusobacterium nucleatum (Fn) is a dominant bacterial species in colorectal cancer (CRC) tissue that is associated with cancer progression and poorer patient prognosis. Following a small-molecule inhibitor screen of 1,846 bioactive compounds against a Fn CRC isolate, we find that 15% of inhibitors are antineoplastic agents including fluoropyrimidines. Validation of these findings reveals that 5-fluorouracil (5-FU), a first-line CRC chemotherapeutic, is a potent inhibitor of Fn CRC isolates. We also identify members of the intratumoral microbiota, including Escherichia coli, that are resistant to 5-FU. Further, CRC E. coli isolates can modify 5-FU and relieve 5-FU toxicity toward otherwise-sensitive Fn and human CRC epithelial cells. Lastly, we demonstrate that ex vivo patient CRC tumor microbiota undergo community disruption after 5-FU exposure and have the potential to deplete 5-FU levels, reducing local drug efficacy. Together, these observations argue for further investigation into the role of the CRC intratumoral microbiota in patient response to chemotherapy.
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Affiliation(s)
- Kaitlyn D LaCourse
- Human Biology Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Martha Zepeda-Rivera
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Andrew G Kempchinsky
- Human Biology Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Alexander Baryiames
- Human Biology Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Samuel S Minot
- Data Core, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Christopher D Johnston
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA 98109, USA.
| | - Susan Bullman
- Human Biology Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA 98109, USA.
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5
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Galeano Niño JL, Wu H, LaCourse KD, Kempchinsky AG, Baryiames A, Barber B, Futran N, Houlton J, Sather C, Sicinska E, Taylor A, Minot SS, Johnston CD, Bullman S. Effect of the intratumoral microbiota on spatial and cellular heterogeneity in cancer. Nature 2022; 611:810-817. [PMID: 36385528 PMCID: PMC9684076 DOI: 10.1038/s41586-022-05435-0] [Citation(s) in RCA: 168] [Impact Index Per Article: 84.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 10/10/2022] [Indexed: 11/17/2022]
Abstract
The tumour-associated microbiota is an intrinsic component of the tumour microenvironment across human cancer types1,2. Intratumoral host-microbiota studies have so far largely relied on bulk tissue analysis1-3, which obscures the spatial distribution and localized effect of the microbiota within tumours. Here, by applying in situ spatial-profiling technologies4 and single-cell RNA sequencing5 to oral squamous cell carcinoma and colorectal cancer, we reveal spatial, cellular and molecular host-microbe interactions. We adapted 10x Visium spatial transcriptomics to determine the identity and in situ location of intratumoral microbial communities within patient tissues. Using GeoMx digital spatial profiling6, we show that bacterial communities populate microniches that are less vascularized, highly immuno‑suppressive and associated with malignant cells with lower levels of Ki-67 as compared to bacteria-negative tumour regions. We developed a single-cell RNA-sequencing method that we name INVADEseq (invasion-adhesion-directed expression sequencing) and, by applying this to patient tumours, identify cell-associated bacteria and the host cells with which they interact, as well as uncovering alterations in transcriptional pathways that are involved in inflammation, metastasis, cell dormancy and DNA repair. Through functional studies, we show that cancer cells that are infected with bacteria invade their surrounding environment as single cells and recruit myeloid cells to bacterial regions. Collectively, our data reveal that the distribution of the microbiota within a tumour is not random; instead, it is highly organized in microniches with immune and epithelial cell functions that promote cancer progression.
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Affiliation(s)
| | - Hanrui Wu
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | | | | | | | | | - Neal Futran
- University of Washington Medical Center, Seattle, WA, USA
| | - Jeffrey Houlton
- University of Washington Medical Center, Seattle, WA, USA
- Head and Neck Specialists, Sarah Cannon Cancer Institute, Charleston, SC, USA
| | - Cassie Sather
- Genomics Core, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Ewa Sicinska
- Department of Pathology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Alison Taylor
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA
| | - Samuel S Minot
- Data Core, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Christopher D Johnston
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
| | - Susan Bullman
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
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6
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Stepanovica M, Zepeda-Rivera MA, McGlinchey AS, Baryiames AA, Jones DS, LaCourse KD, Bullman S, Johnston CD. Complete Genome Sequence of Morganella morganii CTX51T, Isolated from a Human Cecal Adenocarcinoma. Microbiol Resour Announc 2022; 11:e0006622. [PMID: 35254123 PMCID: PMC9022561 DOI: 10.1128/mra.00066-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 02/09/2022] [Indexed: 11/20/2022] Open
Abstract
We report the complete genome sequence of Morganella morganii CTX51T, a strain isolated from the resected tumor of a patient with cecal colorectal adenocarcinoma of the cecum. The genome comprises a circular chromosome of 4.19 Mbp, with an overall GC content of 50.4% and one circular plasmid of 8.48 kbp.
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Affiliation(s)
- Marija Stepanovica
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Martha A. Zepeda-Rivera
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Adam S. McGlinchey
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Alexander A. Baryiames
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Dakota S. Jones
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Kaitlyn D. LaCourse
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Susan Bullman
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Christopher D. Johnston
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
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7
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Ting SY, LaCourse KD, Ledvina HE, Zhang R, Radey MC, Kulasekara HD, Somavanshi R, Bertolli SK, Gallagher LA, Kim J, Penewit KM, Salipante SJ, Xu L, Peterson SB, Mougous JD. Discovery of coordinately regulated pathways that provide innate protection against interbacterial antagonism. eLife 2022; 11:74658. [PMID: 35175195 PMCID: PMC8926400 DOI: 10.7554/elife.74658] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 02/16/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial survival is fraught with antagonism, including that deriving from viruses and competing bacterial cells. It is now appreciated that bacteria mount complex antiviral responses; however, whether a coordinated defense against bacterial threats is undertaken is not well understood. Previously, we showed that Pseudomonas aeruginosa possess a danger-sensing pathway that is a critical fitness determinant during competition against other bacteria. Here, we conducted genome-wide screens in P. aeruginosa that reveal three conserved and widespread interbacterial antagonism resistance clusters (arc1-3). We find that although arc1-3 are coordinately activated by the Gac/Rsm danger-sensing system, they function independently and provide idiosyncratic defense capabilities, distinguishing them from general stress response pathways. Our findings demonstrate that Arc3 family proteins provide specific protection against phospholipase toxins by preventing the accumulation of lysophospholipids in a manner distinct from previously characterized membrane repair systems. These findings liken the response of P. aeruginosa to bacterial threats to that of eukaryotic innate immunity, wherein threat detection leads to the activation of specialized defense systems.
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Affiliation(s)
- See-Yeun Ting
- Department of Microbiology, University of Washington School of MedicineSeattleUnited States
| | - Kaitlyn D LaCourse
- Department of Microbiology, University of Washington School of MedicineSeattleUnited States
| | - Hannah E Ledvina
- Department of Microbiology, University of Washington School of MedicineSeattleUnited States
| | - Rutan Zhang
- Department of Medicinal Chemistry, University of Washington School of PharmacySeattleUnited States
| | - Matthew C Radey
- Department of Microbiology, University of Washington School of MedicineSeattleUnited States
| | - Hemantha D Kulasekara
- Department of Microbiology, University of Washington School of MedicineSeattleUnited States
| | - Rahul Somavanshi
- Department of Microbiology, University of Washington School of MedicineSeattleUnited States
| | - Savannah K Bertolli
- Department of Microbiology, University of Washington School of MedicineSeattleUnited States
| | - Larry A Gallagher
- Department of Microbiology, University of Washington School of MedicineSeattleUnited States
| | - Jennifer Kim
- Department of Microbiology, University of Washington School of MedicineSeattleUnited States
| | - Kelsi M Penewit
- Department of Laboratory Medicine and Pathology, University of Washington School of MedicineSeattleUnited States
| | - Stephen J Salipante
- Department of Laboratory Medicine and Pathology, University of Washington School of MedicineSeattleUnited States
| | - Libin Xu
- Department of Medicinal Chemistry, University of Washington School of PharmacySeattleUnited States
| | - S Brook Peterson
- Department of Microbiology, University of Washington School of MedicineSeattleUnited States
| | - Joseph D Mougous
- Department of Microbiology, University of Washington School of MedicineSeattleUnited States,Department of Biochemistry, University of Washington School of MedicineSeattleUnited States,Howard Hughes Medical Institute, University of WashingtonSeattleUnited States
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8
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LaCourse KD, Johnston CD, Bullman S. The relationship between gastrointestinal cancers and the microbiota. Lancet Gastroenterol Hepatol 2021; 6:498-509. [PMID: 33743198 PMCID: PMC10773981 DOI: 10.1016/s2468-1253(20)30362-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 11/17/2020] [Accepted: 11/19/2020] [Indexed: 02/07/2023]
Abstract
The contribution of the microbiota to disease progression and treatment efficacy is often neglected when determining who is at the highest risk of developing gastrointestinal cancers or designing treatment strategies for patients. We reviewed the current literature on the effect of the human microbiota on cancer risk, prognosis, and treatment efficacy. We highlight emerging research that seeks to identify microbial signatures as biomarkers for various gastrointestinal cancers, and discuss how we could harness knowledge of the microbiome to detect, prevent, and treat these cancers. Finally, we outline further research needed in the field of gastrointestinal cancers and the microbiota, and describe the efforts required to increase the accuracy and reproducibility of data linking the microbiome to cancer.
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Affiliation(s)
- Kaitlyn D LaCourse
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Christopher D Johnston
- Vaccine and Infection Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Susan Bullman
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
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9
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LaCourse KD, Peterson SB, Kulasekara HD, Radey MC, Kim J, Mougous JD. Conditional toxicity and synergy drive diversity among antibacterial effectors. Nat Microbiol 2018; 3:440-446. [PMID: 29459733 PMCID: PMC5876133 DOI: 10.1038/s41564-018-0113-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 01/16/2018] [Indexed: 12/19/2022]
Abstract
Bacteria in polymicrobial habitats contend with a persistent barrage of competitors, often under rapidly changing environmental conditions1. The direct antagonism of competitor cells is thus an important bacterial survival strategy2. Towards this end, many bacterial species employ an arsenal of antimicrobial effectors with multiple activities; however, the benefits conferred by the simultaneous deployment of diverse toxins are unknown. Here we show that the multiple effectors delivered to competitor bacteria by the type VI secretion system (T6SS) of Pseudomonas aeruginosa display conditional efficacy and act synergistically. One of these effectors, Tse4, is most active in high salinity environments and synergizes with effectors that degrade the cell wall or inactivate intracellular electron carriers. We find Tse4 synergizes with these disparate mechanisms by forming pores that disrupt the ΔΨ component of the proton motive force. Our results provide evidence that the concomitant delivery of a cocktail of effectors serves as a bet-hedging strategy to promote bacterial competitiveness in the face of unpredictable and variable environmental conditions.
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Affiliation(s)
| | - S Brook Peterson
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | | | - Matthew C Radey
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Jungyun Kim
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Joseph D Mougous
- Department of Microbiology, University of Washington, Seattle, WA, USA. .,Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA.
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